Fluid operated electric switch



Jan. 12, 1932. Q CARPENTER 1,840,696

FLUID OPERATED ELECTRIC SWITCH Nlllllllllllllllm 3" mm mlnumluj 35 nlm Jan. l2, 1932. C, E CARPENTER 1,840,696

FLUID OPERATED ELECTRIC SWITCH Filed Dec. 5, 1930 4 Sheets-Sheet 2 WMM" 40 j@ eg Jan. 12, 1932.

C. E. CARPENTER FLUID OPERTED ELECTRIC SWITCH Filed Dec. 5, 1930 4 Sheets-Sheet 5 FlG. 5.

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Jan. 12, 1932. v C, E, CARENTER 1,840,696

FLUID OPERATED ELECTRIC SWITCH Filed Dec. 5, 1930 4 Sheets-Sheet 4 FIG. 7.

,I mi 32 MW 20 FIGS.

Patented Jan.. 12, 1932 UNITED STATES PATENT oi-FlcE FLUID OPERATED ELECTRIC SWITCH Application led December 5, 1930, Serial No. 500,168, and in Great Britain Ian-nary 29, 1926.

The invention relates to a fluid-operated with mechanism combined into a single unielectric switch.

The present application is 'a .continuation in part of the prior applications Serial NoL 731,282, August 11, 1924, and Serial No.

180,599, April 2, 1927, filed by the same applicant.

The fluid-operated switch to which the 1nvention is ordinarily applied is operated by a fluid motor, such as a. piston arranged with-4 in a cylinder and having oil or other suitable fluid circulated through its cylinder by a gear or other positive displacement pump, to vary the pressure therein and thereby operate the switch in .accordance with pump speed.

The prior applications set forth electric motor control apparatus in which such an electric switch is -employed to control the operation thereof.

The electric switch as shown in said applications has its pump driven in accordance with the speed of an electric motortovary the pressure in the fluid motor and vthereby operate the electric switch to control the electric motor control apparatus in accordance with the speed of the electric motor.

The invention has as an object to close the switch at a given or critical pump speed.

Another object is to lessen the increase in pressure in the cylinder upon further increase in the pump speed after the switch has been closed. c

Another object is to lessen the decrease in pressure in the fluid motor upon decrease in the pump speed before the switch is opened. y

Another object is to maintain sufficient pressure in the fluid motor to keep the switch o closed upon decrease in the pump speed until below the critical or given pump speed to close the switch.

Another object is to keep the switch closed until the pump is stopped or its speed is low. Another object is to cause the switch to have a quick action in being closed. Another object is to enable the switch to be adjusted to be closed at different pump speeds. I Another object is to provide the switch tary appliance.

Another object is to provide a switch which may be readily assembled and disassembled and which is capable of being readily and economically manufactured.

According to the invention as exemplified herein and ordinarily embodied in practice, the fluid motor has its piston act as a valve to regulate and control the pressure exerted by the oil upon the piston ata given pump speed or at different given pump speeds, as appears in the prior applications, but other ways may be employed to obtain the same end.

Other. characteristics which the invention possesses will be apparent from the switches hereinafter set forth.

The accompanying drawings illustrate switches in which the invention has been employed in practice.

Figures l to 6 illustrate a switch having the piston act as a valve to lessen the increase in pressure in the cylinder after the switch has been closed and to maintain sufficient pressure to keep the switch closed until the pump is stopped or its speed islow, and the views therein are:

Figure 1 is a longitudinal vertical section through the fluid motor, on line 1 1, Fig. 6, showing the switch open;

Figure 2 is the same section through the fluid motor showing the switch closed;

Figure 3 is a transverse vertical section through the fluid motor on line 3 3, Fig. 6;

Figure 4 is a longitudinal vertical section through the gear pump on line 4 4, Fig. 6;

Figure 5 is a transverse vertical section on line 5 5, Fig. 6, through the gear pump; and

Figure 6 is a plan view above the electric switc Figures 7 and 8 illustrate a switch having the piston further act as a valve to cause a sudden increase in pressure at a critical or given pump speed to give the switch a `quick action in being closed, and the views therein are:

Figure 7 is a transverse vertical section through the fluid motorshowing the switch open;

Figure 8 is the same section through the Huid motor showing the switch closed.

The switch as a whole includes an electric switch, a fluid motor, and a gear pump, combined into a single unitary appliance.

The electric switch has a movable switch contact or blade 1 pivoted at its inner end upon a bearing post 2 and movable at its outer or free end between up-contact 3 and downcontact 4.

The Huid motor has a piston 5 arranged withinia cylinder 6 and connected through intervening mechanism to the switch blade.

The gear pump has a driving gear piston 7 and a driven gear piston 8 arranged within a pump casing 9 having a partition 10 between the gear pistons.

The pump discharge port 11 is connected to the cylinder inlet port 12, and the cylinder outlet port 13 is connected to the pump suction port 14.

These ports provide a passage for oil or other suitable fluid to be circulated by the pump through the cylinder.

The driving gear piston is carried and driven by a driving shaft 15 having a bearing in the pump casing and a bearing in the switch casing and extending outside the switch casing to be connected to an electric motor or other power source and driven thereby.

The pump casing has a removable cap or cover 16 retained in place by screw-bolts 17 and having a bearing pintle 18 carrying the driven gear piston.

The electric switch, the fluid motor, and the gear pump are combined into a single unitary appliance within a switch casin 19 having a removable cap 2O at its top an an oil reservoir 2l therein at its bottom.

The motor cylinder and the pump casing are integral with the switch casing and surrounded by the oil reservoir.

The pump casing is provided with an oil supply port 22 connecting its suction port to its oil reservoir.

The bearing for the driving shaft in the switch casing is surrounded by a stuffing box 23 to keep oil leaking therethrough from the oil reservoir.

The electric switch is carried by a removable insulating base 24 supported above the fluid motor and held in place by screws 25.

The bearing post is provided with a binding terminal 26 for connecting thereto an electrical conductor to connect the switch blade in circuit, and the switch blade is convnected to the binding terminal by a contact spring 27 to conduct current thereto around its pivot.

The switch blade has its pivot end shaped to embrace the pivot post and to provide an angular pivot edge to set within a bearing groove in the bearing post.

The up-contact 3 is carried by a bracket 28,

and its position is adjustable by a screw 29 threaded in the bracket.

The bracket is provided with a binding terminal 30 to connect thereto an electrical conductor to connect the up-contact in circuit.

The down-contact is arranged upon the switch base and connected to a binding terminal 31 to connect thereto an electrical conductor to connect it in circuit.

The piston carries a piston rod 32 extending upward through the switch base and switch blade and free to move therethrough.

The switch base and the piston have arranged therebetween around the piston rod a piston spring 33 to act in opposition to the pressure within the cylinder and urge the piston to its initial position.

The piston is kept from turning in the cylinder by a fixed guide pin 34 fastened upon the cylinder alongside the piston and a removable guide plate 35 fastened upon the piston and having the guide pin arranged in a notch in the edge thereof.

The switch blade is arranged between a lower insulating collar 36 and an upper insulating collar 37 upon the piston rod.

The upper collar is threaded upon the piston rod and the lower collar has the piston rod free to move therethrough.

The piston rod has arranged thereon between the lower collar and the piston a switch spring 38 and a loose sleeve 39.

The piston may have its initial position in the cylinder adjusted by the upper collar and the upper collar is held from turning upon the piston rod by a lock-nut 40 after the piston has had its initial position adjusted.

When the piston is moved upward, the switch spring raises the sleeve and thereby the switch blade is moved from the downcontact to the up-contact to close the switch.

The piston may then move further upward by compressing the switch spring, as the piston rod is free to move through the sleeve and the lower collar.

The switch, in addition to controlling a circuit through the up-contact, may control an independent circuit through the down-contact.

The switch casing has a conduit 41 for electrical conductors connected to the switch binding terminals to connect the switch in circuit.

The piston forms at its lower end a relief valve to control the cylinder outlet port and thereby control the passage for oil to circulate through the cylinder.

lVhile the pump is idle, the piston is in its initial position and closes the cylinder outlet port.

The piston has its initial position preadjusted by the upper collar to set it to close the switch at a predetermined critical pump speed.

When the pump commences to operate and its speed increases, the piston is raised at the critical speed set by its preadjusted initial position.

The switch is then closed and the cylinder outlet port commences to open.

When the cylinder outlet port is open, the pump circulates the oil through the cylinder from the pump discharge -port to the pump suction port.

If the pump increases its speed above the critical speed, the piston further opens the cylinder outlet port to allow more oil to flow therethrough.

The increase in pressure upon increase in pump speed is thereby lessened and kept from becomingexcessive.

When the pump decreases it's speed, the piston lowers and commences to close the c linder outlet port.

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The decrease inpressure upon decrease in the pump speed is thereby lessened and sufficientl pressure is maintained to keep the switch close to below the critical pump speed.

The up-contact may be preadjusted by its screw to keep the switch closed until the pump is stopped or about to stop.

Figs. 7 and 8, which illustrate a modified switch, have the same reference numerals as Figs. l to 6 to 'designate corresponding parts.

The modified switch is the same as the switch which has been hereinbefore eX- plained, save that its piston is modified to give the switch blade a quick action in closing the switch.

The piston is provided with a lateral piston port 42 and an open bottom chamber 43.

When the piston is in its initial position, the piston port opens a restricted passa-ge for oil to circulate through the cylinder.

When the piston moves upward at the critical speed, the piston port is closed and stops the oil from its initial circulation, and thereby a sudden increase in pressure is obtained to cause the piston to give the switch blade a quick action in closing the switch.

The pist-on port is arranged to be closed coincident with the cylinder outlet port being opened.

Various fluid-operated switches may be devised embodying the invention herein set forth and `defined in the hereinafter claims.

The invention which has been herein set forth is hereby claimed as follows:

1. A fluid-operated electric switch comprising an electric switch, a fluid motor to operate said switch, a pump to create fluid pressure in said fluid motor, and means to lessen the increase in pressure in said fluid motor upon further increase in the pump speed after said switch has been. operated.

2. A fluid-operated electric switch comprising an electric switch, a fluid motor to close said switch, a fluid pump to create fluid pressure in said fluid motor, and means to lessen the increase in pressure in said fluid motor upon further increase in the pump speed after said switch has been closed and to lessen the decrease in pressure in said fluid motor upon decrease in the pump speed to keep the switch closed to below said given pump speed.

3. A fluid-operated electric switch comprising an electric switch, a fluid motor to close said switch, a fluid pump to create fluid pressure in said fluid motor, and means to lessen the increase in pressure in said fluid motor upon further increase in the pump speed after said switch has been closed and to lessen the decrease in pressure in said fluid motor upon decrese in the pump speed to keep said switch closed until the pump is about to stop.

4. A fluid-operated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating fluid under pressure therethrough, a fluid pump tov circulate fluid through said cylinder and thereby vary the pressure Within said cylinder in accordance with its speed, a piston arranged within said cylinder to control said passage and thereby control the pressure within said cylinder independent of ,said pump and connected to operate said switch.

5. A fluid-operated electric -switch comprising an electric switch, a cylinder having ports to provide a passage for circulating fluid under pressure therethrough, a fluid pump to circulate fluid through said cylinder and thereby vary the pressure within said cylinder in accordance with its speed, a piston arranged within said cylinder to control said passage and thereby control the pressure within said cylinder. independent of said pump and connected to operate said switch, and means to adjust the initial position of said piston in said cylinder.

6. A fluid-operated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating fluid under pressure therethrough, Aa fluid pump to circulate fluid through said cylinder and thereby vary the pressure within said cylinder in accordance with its speed, a piston arranged Within said cylinder to control said passage and thereby control the pressure within said cylinder independent of said pump, and a spring arranged between said switch and said piston to operate said switch.

7.' A fluid-operated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating fluid under pressure therethrough, a fluid pump to circulate fluid through said cylinder and thereby vary the pressure within said cylinder in accordance with its speed, a piston arranged within said cylinder to-control said passage and thereby control the pressure within said cylinder independent of said pump, a piston rodv carried by said piston, a movable lower collar arranged upon said rod and having said rod free to slide therethrough, and a spring arranged between said lower collar and said piston to operate said switch.

8. A fluid-operated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating vHuid under pressure therethrough, a fluid pump to circulate fluid through said cylinder and thereby vary the pressure within said cylinder in accordance with its speed, a piston arranged within said cylinder to control said passage and thereby control the pressure within said cylinder independent of said pump and connected to operate said switch, a piston rod carried by said piston, a movable lower collar arranged upon said rod, a spring arranged between said lower collar and said piston to operate said switch, and an upper collar arranged upon said connecting rod and having its position thereon adjustable to adjust the initial position of said piston in said cylinder.

9. A fluid-operated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating iuid under pressure therethrough, a fluid pump to circulate fluid through said cylinder and thereby vary the pressure within said cylinder in accordance with its speed, a piston arranged within said cylinder to control said passage and thereby control the pressure within said cylinder independent of said pump and connected to operate said switch, a piston rod carried by said piston, a movable lower collar arranged upon said rod, a spring arranged between said lower collar and said piston to operate said switch, an upper collar arranged upon said connecting rod and having its position thereon adjustable to adjust the initial position of said piston in said cylinder, and a spring to return said piston to its initial position.

l0. A fluid-operated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating fluid under pressure therethrough, a fluid pump to circulate iuid through said cylinder and thereby vary the pressure within said cylinder in accordance with its speed, a piston movable within said cylinder to control said passage to increase the Huid passed therethrough upon an increase in pump speed above a given or critical speed and connected to operate said switch.

l1. A fiuidoperated electric switch comprising an electric switch, a cylinder having ports to provide a passage for circulating fluid under pressure therethrough, a fluid pump to circulate fluid through said cylinder` and thereby vary the pressure within said cylinder in accordance with its speed, a piston movable within said cylinder to control said passage to increase the fluid passed therethrough upon an increase in pump speed above a given or critical speed and to de- 'CHARLES E. CARPENTER.

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